You don't get to discount pre-production. It's part of the development process and where a lot of story, art, and character design is done. The dozens of artists on staff do a lot of work during these periods and this time is attributed to that game.  If you cut out pre-production, then nearly all of the development hell games you hear about have half or shorter dev times. It's deceiving.

Yes, he specifically mentioned big open world and freedom like was at beginning in Zelda NES.

When they later went full 3D Zelda game, they couldn't go again with big open world and freedom because of limitations of hardwares, till Wii U arived.

I thought MM had 5. But anyways, I know this, but if you stop to think about it... since Majora's the number went up, except for SS. It also became harder to develop new engines for more powerful systems. During the N64 era games would come after 2 years without big problems, everything was easier (I kinda miss those days).

I think the more important issue is when Nintendo starts making the game. VS how long it takes. Great, the game takes 5 years. We know this process is a complicated matter. But they do have planning issues, when they make games. If this happened on TV shows. They be cancelled after one season.

A TV show is made several months to almost a year in advance, before airing. So when you saw that season 1 cliffhanger. 5 episodes where already being planned/written for season 2. To get stuff completed on time. Nintendo needs to start building Zelda games before the generation ends. So that when that zelda comes out during year 3 or 4. The next one is ready at the next generations year 2. Nintendo talking about first time making a HD zelda, is really sad. They basically admitted to no one, on their teams ,did HD tests for Zelda. Till the main build phase started.

No internal demos. No use of portions of Skyward Sword. To test how long a room would take to build in HD, than in SD. Nothing? That be like people in the movie/TV industry designing an outfit. Picking it. It's made for the actor. And they just start filming. When the outfits need to go in front of camera, for testing. To see if it works. Or feels right for the actor.

Simple, Nintendo is still adapting to HD. Many recent nintendo games have taken a longer than anticipated development time due to this. Nintendo was probably in for a shock when they realized just how difficult making an HD open world game for the first time to certain fan expectations was gonna be

This. Prettu much this. They are innefficient.

During the N64 era they faced the worst problem: translate the franchise to 3D.

But their first 3D LoZ knocked it out of the park and is still the highest sold in the franchise as well as the highest overall rated game of all time. Just saying that certain problems will take different amounts of time to overcome. It almost seemed like Mario and LoZ almost went to 3D like it was second nature. Sonic's problem is how do you retain a fast game that incorperates 3D (they shouldn't have once they realized their games couldn't really do much beyond the Adventure titles and reverted back to 2D when they became a 3rd party dev). Making a game that is HD and retains a high frame rate I think would be tougher than just making 3D polygon games. Maybe Nintendo just makes it look easy. 

I disagree.

They have to find the bases and nature of the Zelda franchise in a 3D space. For example, Miyamoto stated that in the first phase of the project, Zelda 64 was something like Mario 64: Link will be all the time in Ganon's Castle (hub) and will enter different dungeons, but all the time in the same big dungeon. That without counting mechanics (like the Z-targeting), artstyle, weapons, puzzles, etc.

Making an HD game with the bases already in their hands is easier than the development of Ocarina of Time, a game whose many ideas where left for a sequel/expansion (Gaiden=Majora's Mask) or never released (Zelda Ura).

Hopefully a TP gets a HD remake for this year. Seen some retailers list Dec 2016 for the new Zelda.

Which retailers?

I know is a placeholder but didn't know about it.